Control valve for hydraulic actuating cylinders



CONTROL VALVE FOR HYDRAULIC ACTUATING CYLINDERS Filed June 10, 1948 L. E. BALDWIN June 9, 1953 2 Sheets-Sheet l DW/N,

INVENTOR.

I qrroe/va LEE 5' 5m 1.. E. BALDWIN 2, 41,279 CONTROL VALVE FOR HYDRAULIC ACTUATING CYLINDERS 2 Sheets-Sheet 2 June 9, 1953 Filed June 10, 1948 /m /V Q6 4 m A e 5 I m, m Tu W 7 n M. S/W 5 VL A i in M i fi%L s A w V M 7 V a M v v, @w MA wm s V V A A W M A fi L 55 5. BfiLDW/N,

JNVENTOR.

armeues Patented June 9, 1953 UNITED CONTROL "ALVE FO'R- HYDRAULIC ACTUATING CYLINDERS Lee E. Baldwin, Glendale, Calif., assignor to Weston Hydraulics, Limited, North Hollywood, Calif., a corporation of California Application June 10, 1948, Serial No. 32,178

9 Claims.

My invention relates generally to hydraulic control valves and more particularly to a valve of this class which is adapted for use in conjunction with a hydraulic actuating cylinder and which is characterized. by a relatively low pressure drop across the valve.

The hydraulically powered controls in aircraft, in machine tools, in many other devices, are often actuated by a double acting piston used in conjunction with a pump and fluid reservoir, a selector valve being employed in the hydraulic system to control the mechanical motion of the actuator piston.

The usual hydraulically powered actuating cylinder is so arranged that fluid may be introduced into the cylinder selectively on one or the other side of the piston, thus forcing the piston to move in one or the other direction as desired. Simultaneously with the introduction of fluid into the pressure or power side of the hydraulic cylinder, it is, of course, necessary to provide for the exit of fluid from the exhaust of the iston or cylinder. It is desirable furthermore to accomplish this control of the hydraulic fluid in a single operation. It is in a valve for the just stated purpose that the present invention is embodied.

Selector valves of the type just described have been designed previously but have had certain disadvantages, particularly where rapid motion of the actuating piston is desired. It will be obvious thatwhen such rapid motion is desired, the rate of flow of fluid into the power side of the cylinder and out of the exit side thereof must be relatively rapid. If the selector valve employed to control the entrance and exit of fluid presents an appreciable resistance to the flow of fluid therethrough, the rapid actuation of the piston is greatly impaired.

Bearing in mind the above stated diificulties, it is a major object of my invention to provide a. selector valve for the purpose stated, in which the fluid pressure drop across the valve at relatively high rates of fluid flow, is relatively low.

Another object of my invention is to provide a valve of the class described which employs a hydraulic relay system in connection with a pair of solenoid valves whereby to make possible the electrical control of the selector valve.

Still another object of my invention is to provide a valve of the class described which may be either electrically or manually operated.

A still further object of my invention is to-provide a valve of the class described which is relatively simple as to the number and complexity of its parts, and is relatively light in weight whereby to adapt the valve for use in aircraft hydraulic systems.

The foregoing and other objects and advantages of my invention will become apparent from a consideration of the following detailed descrip-- tion thereof. such description being considered in connection with the attached drawings, in which:

Figure I is a semi-schematic perspective view, illustrating a valve embodying my invention as incorporated in a simple hydraulic system;

Figure 2 is an enlarged elevational section taken on the-line 22 in Figure 1 'Figure 2a is a semi-diagrammatic vieu of the valve similar to Figure 2 and showing certain fluid connections therein;

Figure 3 is an enlarged fragmentary eleva tional section, taken on the line 33 in Figure 2;

Figure 4 is an enlarged elevational section taken on the line 4-4 in Figure 2;

Figure 5 is a perspective view of a sleeve member employed in the device illustrated in Figures 1 and 2; and

Figures 6 and l are operational drawings being fragmentary sections taken on the line @5 in Figure 4, portions of the device being eliminated from the drawings for purposes of clarity.

The valve assembly embodying my invention is indicated throughout the drawings by the reference character i0, and. includes a main body member H of generally cylindrical shape, into the ends of which are threaded two identical end caps 12, the body i I having in addition a flanged attachment member 13 secured to a side thereof by bolts M. A pair of operating handles it is provided, each handle projecting from an end of the body I Compression springs it are mounted around the shanks of the handles it and adapted to urge the latter outwardly of the body I i.

The flanged attachment member i3 is provided with five threaded nipples l'i--2 I, adapted to receive conventional tube fittings for connection of the valve It into a hydraulic system. The tube-connecting nipples l'l and IS are, as shown in Figure 1, connected to the two ends of a double acting cylinder 25 having a piston 25 therein and a connecting rod 2'! secured to the piston in the conventional manner. In installations Where it is desired to maintain the rate of change of volume of the two portions of the cylinder 25 equal, an additional connecting rod can be secured to the piston to extend in the opposite direction from the connecting rod 21.

The centrally located attachment nipple i 9 on the attachment member i 3 is connected to a fluid pump it which pump is in turn connected for a supply of fluid to a reservoir 3!. The pump 3i! may be driven by any suitable power means (not shown) and serves to drive fluid in a direction indicated by the arrows placed on the dotted line fluid conduits indicated. schematically in Figure l. The end tube connection nipples 25 and 2! are connected to the reservoir iii and serve to return fluid thereto.

In the following discussion, a power stroke of the piston 26 which draws the connecting rod toward the cylinder 25 will be referred to as a pull stroke and motion of the piston in the opposite direction will be referred to as a thrust stroke. The portions of the cylinder 25 to the left and the right of the piston 26 in Figure 1 will be referred to as the upper and lower cylinder portions 23 and 24, respectively.

For a detailed description of the interior parts of the valve ID, reference should now be had to Figures 2 and 2a. Here it will be seen that the tube attachment nipples I! through 2I communicate with various annularly shaped chambers within the body II. These chambers, to be referred to hereinafter as manifolds, include a central pressure manifold 35 which communicates with the central attachment nipple I9, a pair of intermediate cylinder feed manifolds 36 and 3! which communicate with tube attachment nipples I1 and I8, respectively, and a pair of terminally located return manifolds 38 and 39 having communication with the end tube attachment nipples 2| and 29, respectively.

All the foregoing manifolds are cast within the body I I and have a peculiar cross-sectional shape to be described later herein. A common inner wall for all of the manifold chambers 35 through 39 is formed by an internal sleeve 40 (shown separately in Figure which is fixed within an interior bore of the body I I and secured therein by a pair of end bushing members II and 42, which members are in turn secured in the body II by the end caps I2. Suitable O-ring gaskets 43 are provided surrounding the sleeve 40 at various points whereby to hermetically separate the various manifold chambers from each other.

Arranged in circumferential rings adjacent the internal opening of each of the manifold chambers are a series of square orifices 44 through the wall of the sleeve 40 which serve to communicate the annular chamber 35, 36, 31, 38 and 39 with the interior of the sleeve 40.

Within the sleeve 40 and slidable therein is a hollow and generally cylindrical member 50, re-

ferred to herein as a spool. It will be noted that the spool 50 has a number of exterior annular grooves 5|, 52 and 53 therein, which form transition chambers arranged to underlie various groups of the orifices 44 as will be hereinafter described.

As above mentioned, the spool 50 is slidable 1ongitudinally within the sleeve 43. It is the longitudinal sliding motion of the spool 50 which serves to intercommunicate various of the tube attachment nipples I I through 2|, thus to actuate the hydraulic cylinder 25 in the direction desired. The power required to move the spool 50 in one direction or the other is derived from the fluid pressure itself. To this end, the pressure manifold 35 is communicated through two rows of orifices 44 as indicated in Figure 2 into a central recess 5| in the spool 50 and thence through a radial passage 60 in the spool 50 into a central bore GI thereof.

A pair of fixed piston-like members '62 project inwardly into the bore GI and are provided at their inner ends with O-rings 63 whereby to form a hermetic seal with the interior bore SI of the spool 50. The piston members 62 are secured in fixed position by compression springs 64 anchored against flanges 65 formed in their outer ends, the compression springs 64 thrusting at their inner ends against the ends of the spool 50, a washer 66 being interposed between the end of each spring and the corresponding end of the spool. It will be noted from an examination of Figure 2 that an enlarged interior recess 6! is formed in each end of the sleeve to receive the washer 66. By this arrangement, it will be seen that either end of the spool 50, when moving outwardly, moves the washer '56 and thus encounters the thrusting resistance of the compression spring 64. Inward motion of the spool end, however, is not followed by inward motion of the washer 66.

The result of the above arrangement is that the spool moves independently of the piston members 62, these members having sliding engagement with the interior bore 6| whereby to permit such motion of the spool 50.

The operation of the movable spool 50 will become apparent from an examination of Figures 6 and 7, wherein the spool is shown in two successive positions, that in Figure 6 being a neutral position, and that in Figure '7 the position wherein the spool has been moved to the left. Since the valve illustrated herein is bi-laterally symmetrical, a description of one mode of operation suffices to disclose the principle involved in all modes of operation.

Referring specifically to Figure 6, it will be seen that the piston members 62 are provided with interior bores 10 to permit axial passage of fluid tlierethrough. At the outer end of each of the piston members 62 is a valve seat lI adapted to be closed by a check ball I2. Normally, the check ball I2 is held in an outward position against a second valve seat I3 formed in the inner end of an axial fluid passage I4 in the bushing member 4 I, the ball being held in this position by the fluid pressure transmitted through the axial passage 10 in the piston member 62. It should be noted 4 that, by reason of the check ball I2 being mengagement with the seat I3, the fluid pressure within the spool 5!! is confined to the generally cylindrical chambers 15 formed in the bushing members 4| adjacent the ends of the spool. Escape of fluid from the chambers 15 is prevented by the O-ring gaskets 43 which surround the sleeve 46 immediately adjacent its end.

It will also be noted that the end of the spool 50 forms a movable wall for the chamber I5 in each of the bushing members 4 I. Since the fluid pressure is equal in each of the chambers 15 and since the spool ends are the same diameter, the fluid pressures acting on the ends of the spool 50 balance each other and there is no resultant force tending to move the spool 50 in either direction so long as both of the check balls 72 are seated against the seats 13 in the bushing members 4 I.

Mounted within each of the end caps I2 is a solenoid coil 80, connected by suitable leads 8| to a four-conductor electrical connector 82, mounted on the lower side of the body II and being provided with a conventional threaded connector sleeve 83. The electrical connector plug 82 is sealed with an O-ring gasket 84 to prevent the escape of fluid from within the body I I.

Both the bushing member 4| and the shank 85 of the handle I 6 are constructed of ferro magnetic material and since both of these members project within the solenoid coil but are slightly separated therein, as best seen in Figure 2, a powerful magnetic attraction between the shank and the bushing member 4I is effected when the solenoid coil 80 is energized. As seen in Figure 2, and as further illustrated in Figure 3, the shank 85 is provided at its inward end with a triangularly cross-sectioned thrust pin 86, which projects through the fluid of the bushing member "4| through a :passage 1 81 *in to the fluid' -return manifold 38. :Bywthi-s escape of fluid through the passage l l, the fluid pressure in the particular chamber 15 in which -the eheok -ba1l "M is actuated, is relieved, and -furthermore, since the axia'hpassage l E] imthe piston "member 62 is blocked, 'such "fluid pressure is not replenished. Accordingly, the fluid pressure against one end of the spool 5%! is relieved, and the result is that the fluid. pressure acting on the opposite end causes -'the spool to be-moved longi- -tudinally as shownin Figure? The result of longitudinal motion of the spool 51] will now fbedescribed. 'Itwill be remembered that the spool 150 is provided, in its exterior surface, with a number-of circumferential grooves 51 52 and 53. Consideringtheposition ofthe spool -58 in'Figurefl, it will be seen thatthe circuniierentiaLgroove fi'z underlies those orifices dlwhich communicate with thejintermediate manifold 36 and the-terminalmanifold as. Thus itis possible for fluid to flow from the manifold "'36 inwardly toward the spool, axially along the groove 52 and outwa rdly through ,orifices 44 "into the terminal or'iluid return manifold 38.

"Recalling the connections of the fluid conduits, it will be seen that the result of this positioning (if the circ mfer ntial g ove 52 i permi jlui'cl'to .esca peirpm theupper cylinder chamber "is through the valve [0 and thene'to the reser- 9 .l pursafitlis necessary, th 'fiuid s t move out of the upper qy jin'der chamber 23 that force be exert d by h ton Such f ce, pr ducin the af re aid "fpi ll rokef i c s o d by the Sta th t the c cumfer n a r ve "5:3 in thespoo 15,0 und r ies or fic s in a anne to inte connec th fl i res manif ld *35 with the intermediate manifold 31, thus to .permitt fluid IrQ th pump '30 osas t r ugh h va v and nt t e lo e cyl nder chamb r -4- I s obvious thatmotiqn ,of the. spo in the direction opposite to that shown in Figure .7 is le fiected by actuating the solenoid at the right end of the spool as shown in Figure '7, producinga fthrust stroke ,of the piston 2&5.

I will be note from an xamin t on f Fi ures 2 and 5that'the orifices M are-square. The purpose in making these orifices square instead of wound is to permit :a maximum flow 501f afluid through the orifices while maintaining a mini- .mum :motion ,of .the spool so required to close the orifices. ,One advantage of using square orifices at ills is that ,such shape lpermitsian optimum rate ;of flow consistent with a relatively short longitudinal dimension. Furthermore, square orifices are relatively simple to produce compared, forexample, to transverse slots. While transverse slots would give :a greater lfiow :area, they would seriously interfere with the free :sliding action of the spool 511.. Thus, it has been '6 dound that the'square shape-gives optimum resuitsingthewalveshown.

As a furtherlmeasurewto'zreduce the ifluidiresist- :anoe in the walue 1| 0, ithe manifolds :35 *through 39 are taperedias indicated 5111 Figures s2 and 4. In Figure :14, it will lbe :seen that the .upper lapvproximatelyzone-ihalf .of time vmanifold .is :of relatively great crossssectionnsince the :fluid ipassing therethrough must the sufli-cient to :supply not only the orifices 44 in the upper part of thevsleeve til tas viewedin @igure 14") butmust supplysufii- "cient fluid to pass=on around the "sleeve 5'40 and into the orifices W4 alongfthe :lower portionrof :the periphery of the :sleeve (E9. in iorder 'to provide "sufficient sealing surface :of the body H against he sleev t'll, the intermediate manifolds :35 and 'sl eremade with anepproximatly il -shaped cross sectionin their upperzportions, :asibestiseen in Figure '2.

The result :of shaping "the Iinterior cross-sec- *ti'on o'f the manifoldsrinithe manner just described -is -to produce a :more nearly laminar :flow of the fiui'd therethrough in oontra-idistinction :to the turbulent --fiow t-ha't is produced if the manifold -'-has a uniform cross-section throughout tt-heir peripheral lengths. it has :been found that the tapered cross-section-ofithe manifolds .veryrmatewria lly decreases *the resistanc .to rapid flow of fluid therethrough.

"It will be obvious that, should it be desired :to -manually operate the valve t0, manual cpressure may be applied to eit-her of the handles :rs, hav ing the =effect-of moving the check ball T2 in the samemanner as that mode ofoperation achieved by means of the solenoid coil 80.

Thus-it-willbe-seenthat I'have provided a rela- "tively simple, yet highly efilcient, fluid control valve whichfbecause of "its minimum number of ,parts and its relatively light construction, is adapted .for use aircraft fluid controls.

While the device shown and described herein is .fully capable ,of achieving the objects and ,providing ,the advantages hereinbe'fore stated, it .will be realized that it is capable ,of considerable modification by those skilled in the art Without departing from the spirit of z-the invention. Therefore, LI do 111.017 {means *to :be limited to :the dorm shown and described, \but rather to :the scope lot the =-ap.nended claims.

I claim:

1. lln a avalveiof the type having a housing with -a connection to vreceive fluid under pressure and a member in said :housing selectively movable in :one of two -'directions to control the flow .of

said fiuid .under :pressure, actuating means for said member comprising: closure means in said "housing forming :a :pair :of pressure chambers ad- 'jacen't :opposed surfaces of said member; fixed means in said'housingin sliding, fluid tight contact with said :member and cooperating therewith to dorm ;a pair :of inlet ipassages through said member adapted :to deliver said fluid zunder =.pressure from said connection into each 10f said :pressure chambers; :fixed ameans forming a pair of exit :passages, =.one *leading'from each .of said pressure chambers; 1-2, :pair .of how check mem- *bers leach normally positioned in zone of said chambers :to :block lone of .said iexi't :passages'; and means including a pair of separate actuators each positioned adjacent one of said pressure chambers to selectively move one of said flow check :members out ,of said exit :blocki-ng position and into position to block one 2015 said inlet passages whereby rte empty and prevent refill of one of said pressure chambers, and permit movement of said control member under pressure from the other of said pressure chambers.

2. The construction set forth in claim 1 further characterized in that said last mentioned means includes a solenoid actuated thrust member.

3. The construction set forth in claim 2 further characterized in that said solenoid actuated member includes a handle to permit selective manual operation thereof.

4. A fluid valve of the class described, comprising in combination: a body having a cylindrical bore therein, said bore having annular recesses formed therein opening into said bore at spaced points therealong, and said recesses having a cross-sectional area which varies around the circumference thereof being relatively greatest at one point and relatively smallest at a point diametrically opposite therefrom; means forming a plurality of conduit connections on said body, each of said conduit connections being connected by a passage to saidmaximum area point in one of said recesses; a sleeve in said bore having a plurality of groups of circumferentially arranged square orifices formed therein, each of said groups underlying one of said recesses whereby to communicate the latter with the interior of said sleeve; gasket means surrounding said sleeve at intervals thereon between each of said recesses whereby to hermetically separate said recesses from each other except through said orifices; an axially slidable valving member in said sleeve having sealing contact with the interior wall thereof, said valving member having a plurality of annular exterior grooves therein adapted and positioned to underlie selected adjacent pairs of said orifice groups whereby to intercommunicate adjacent recesses; a pair of spring members engaged with said valving member and adapted to hold the same in a normally central position in which none of said recesses are intercommunicated; and operable means to move said valving member to various positions in said sleeve whereby to intercommunicate selected pairs of said conduit connections.

5. The construction set forth in claim 4 further characterized in that said last means includes: a pair of end caps in said body adapted to form a pressure chamber adjacent each end of said valving member; means including a fixed piston member in sliding, fluid tight contact with said member and forming fluid inlet passages through said valving member from one of said recesses, said inlet passages being adapted to conduct fluid under pressure into said pressure chambers, said piston member having a valve seat therein; other passage means leading from said pressure chambers to another of said recesses adapted to exhaust fluid from said pressure chambers; a check member in each of said chambers normally blocking the exhaust passage thereof, said check member being adapted to be moved to open said exhaust passage and against said valve seat to close said inlet passage whereby to permit said valving member to be moved by pressure in the opposite pressure chamber to one of said various positions; and thrust means including separate members adjacent each pressure chamber to move one or the other of said check members selectively.

6. The construction set forth in claim 5 further characterized in that said thrust means includes a pair of solenoid actuated thrust pins.

7. The construction set forth in claim 6 further characterized by said thrust pins each having a handle formed thereon to manually operate said valve.

8. In a valve of the type having a housing with a connection to receive fluid under pressure and a member in said housing selectively movable longitudinally in one of two directions to control the flow of said fluid under pressure, actuating means for said member comprising: closure means in said housing forming a pair of pressure chambers adjacent opposed end surfaces of said member; manifold means in said housing to receive fluid under pressure from said connection, said manifold means being connected and adapted to place said fluid under pressure in contact with a side surface of said member; means including a passage in said member to deliver said fluid under pressure to an inlet port in each of said pressure chambers; fixed means forming a pair of exit passages, one leading from each of said pressure chambers; a pair of flow check members each normally positioned in one of said chambers to block one of said exit passages; and a pair of actuators, one for each of said flow check members, each actuator being adapted to move its flow check member out of exit blocking position and into position to block the inlet port of its pressure chamber whereby to empty and prevent refill thereof and permit movement of said member under pressure from the other pressure chamber.

9. In a valve of the type having a housing with a connection to receive fluid under pres sure and a valving member in said housing selectively movable longitudinally in one of two directions to control the flow of said fluid under pressure, actuating means for said member comprising: a pair of expansible chambers formed in said housing, each abutting an end of said valving member whereby movement of said valving member expands one chamber and contracts the other; a non-expansible fluid manifold in said housing to receive said fluid under pressure; means to place said fluid in contact with a side wall of said valving member; a fluid passage in said valving member connecting said manifold with an inlet port in each chamber; an exhaust port in each chamber; a flow check member in each chamber normally positioned by said fluid pressure to block the exhaust port in said chamber and movable from said normal position to open said exhaust port and close said inlet port; and externally operable control means to selectively move one or the other of said flow check members whereby to empty and prevent refill of the chamber in which said flow check member is moved and permit movement of said valving member.

LEE E. BALDWIN.

References Cited in the flle of this patent UNITED STATES PATENTS Number Name Date 358,520 Westinghouse Mar. 1, 1887 393,596 Westinghouse Nov. 27, 1888 463,623 Eichbaum Nov. 24, 1891 867,774 Weir Oct. 8, 1907 910,092 Simonds Jan. 19, 1909 1,711,570 Loomis May 7, 1929 1,935,971 Wuesthoff Nov. 21, 1933 2,031,478 Gray Feb. 18, 1936 2,106,572 Meagher Jan. 25, 1938 2,363,111 Bennett Nov. 21, 1944 2,396,643 Gonahl Mar. 19, 1946 2.460.908 Scott. Feb. 8, 1949 

